Sound-reproducing device



Aug. 4, 1925. 1,548,740

, w. B POTTER SOUND REPRODUC ING DEVI CE Filed Oct. 21. 1924 Inventor William B.F 5tter-,

His Attorney.

Patented Aug. 4, 1925.

UNITED STATES PATENT FFICE.

WILLIAM B. POTTER, OF SCHENECTADY NEW YORK, ASSIGNO'R TO GENERAL ELEC- 'IBIC COMPANY, A CORPORATION OF NEW YORK.

SOUND-REPBJODUCING DEVICE.

Application filed October 21, 1324. Serial No. 745,015.

T 0 all whom it may cmwern:

Be it known that 1, Wins/nu B. PO'I'IER, a citizen of the United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Sound- Reproducing Devices, of which the fo'u win is a specification.

1y present invention relates to sound reproducing devices of the type commonly known in the art of radio reception as loud speakers.

The object of my invention is to rovide an efficient form of device which wil faithfully reproduce in large volume sounds such as music or speech without at the same time producing distortion by reason of resonant eifectsjof vibrating apparatus or resonant air columns.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation will best be understood by reference to the following description taken in connection with the accompanying drawing in which Fig. 1 is a front elevation of a device embodying my invention; Fig.2 is a side elevation with a portion broken away; Fig. 3 is a detail cross section showing the method of drivin a diaphragm constructed in accordance wit my invention; F ig. 4 is a partial cross-sectional view of the diaphra m; and Fig. 5 is a detail illustrating a met 0d of supporting the diaphragm.

I have indicated in the drawing a diaphragm which comprises a cone 1 of light material such as stlfi' paper. The ed e of the base of the cone 1 is bent outwar l to form a flange 2. The cone is reinforce or made rigid 1n order that it may be ca able of vibrating substantially as a who e by means of the frustrum 3 of another cone of the same diameter. The edge of the base of the frustrum 3 is bent outwardly to form a flange 4, which may be secured to the flange 2 by any suitable adhesive. The frustrum 3 is open at its to and the upper edge may be bent outwar y at 5 and reinforced b means of a' reinforcing band 6 to add r1- gidity to the structure.

The dia hragm as described is flexibly supported rom the periphery of the base of the cone 1 by means of cords 7 passing through and tied to eyelets 8 formed in the base flange. The cords 7 may be threaded through holes 9 in a supporting ring 10 and wound around the screws 11. The cords 7 may be drawn up to a desired tension andsecured by tightening the screws 11. The supporting ring 10 may be formed of a strip of metal having its ends secured together by a bolt 12, The ends of the'stri may also be bent into a common plane and secured to a supporting base 13 by means of screws 14.

The diaphragm thus constructed and supported may be actuated by any desired form of driver. I have indicated in Fig. 3 in a.

more or less diagrammatic manner one wa m wluch the diaphragm. may be actuate 1 have shown an actuating means com rising in its essential aspects a common orm of telephone receiver having a vibrating diaphragm 14 in proximity to pole pieces 15 of a magnet which are surrounded by coils 16 to which actuating currentsmay be supplied. A rod 17 is secured to the diaphragm 14 by means ofa screw 18. The apex of the cone 1 is preferably reinforced by means of reinforcing members 19 and rod 17 is secured to the apex of the cone by means of a screw 20. The actuatin means may be secured by a clamping mem er 21 to a standard 22, which in turn is supported by the base 13.

I have found that a diaphragm constructed and supported as described may be made toreproduce with great accuracy any desired sounds. I Because of the flexible support the diaphragm is under little restraint and tends to vibrate as a Whole. Resonant effects common to diaphragms which are under restraint are largely eliminated.

By making the area on to of the frustrum 3 materially less than t e area of the base of the cone 1, the sounds produced in the interior of the cone 1 are pro agated more or less in beam fashion instea of being transmitted through a wide area. At the same time the sounds produced are not confined in any place to such a restricted cross sectional area that there is any resonant air effect introduced such as is common with many horns employed with loud speakers. The shar ness of this directive effect will of course spend to a large extent upon the area of the top of the frustrum 3.

By locating the driving means outside of the cone also there is no obstruction to the free propagation of sounds lrom the entire inner area of the cone.

\Vhile I have shown and described only one embodiment of my invention it will be apparent that many modifications in the manner of carrying it out may be made without departing from the scope thereof as set forth in the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States 1. Soundreproducing means comprising a diaphragm having the form of a hollow cone made rigid by the frustrum of a cone secured to its base, said cone being flexibly sup orted from the peripheryof its base, and actuating means for said diaphragm located outside said cone and secured to said cone at its apex.

2. Sound reproducing means comprising a dia hragm having the form of a hollow cone liaving a frustrum of another cone joined thereto at its base, the top of said frustrum being open and the upper edge thereof being bentoutwardly, said cone being flexibly supported from the periphery of its base, and actuating means for said diaphragm located outside said cone and secured thereto at its apex.

3. Sound reproducing means comprising a dia hragm having the form of a hollow cone Riaving a frustrum of another cone joined thereto at its base, thetop of said frustrum beingopen and the upper edge thereof being bent outwardly and reinforced by a stifi'enin band said cone being flexibly sup orted mm the periphery of its base, an actuating means for said diaphra m located outside said cone and secure thereto at its apex.

4. Sound reproducing means com rising a diaphragm having the form of a ollow cone, made rigid by the frustrum of a cone secured to its base, said cone being flexibly supported from the peripher of its base, and actuatin means for said diaphragm located outside said cone and secured to said cone at its apex, the top of said frustrum being open and havin an area materially less than the area of its base whereby the sound produced at theinner surface of said cone is propagated in beam fashion.

b'ound reproducing means com rising a diaphragm having the form of a ollow cone, a second hollow member having two open ends, one of which is joined to the base of said cone to render it more rigid, means for flexibly supporting said cone from the periphe of its base, and actuating means for sai diaphra' located outside said cone and secure thereto at its apex, said second hollow member being adapted to direct the sound produced at the inner surface of said cone.

In witness whereof, I have hereunto set my hand this 20th day of October, 1924..

WILLIAM B. POTTER. 

